Hepatitis Therapeutic Vaccines
HCV infection is a causative agent of chronic liver disease with worldwide prevalence of 170 million cases. Options are few, if sustained viral clearance cannot be achieved by conventional treatment. Unfortunately, conventional therapies become progressively less effective if chronic hepatitis evolves into cirrhosis. Once cirrhosis develops, treatment is aimed at the management of complications.
Clearly, alternative treatment strategies are needed for chronic hepatitis infections. Such could be the exploitation of the viral competition phenomenon employing non-pathogenic viruses.
The proposed therapy is based on an innovative technological platform the so called "superinfection" therapy. The superinfection therapeutic vaccine strategy exploits viral competition for the treatment of persistent viral infections. The clinical observation that infection by one type of hepatitis virus (e.g. HCV) was often abolished following accidental superinfection by a second hepatitis virus (e.g. HBV) prompted the idea of intentional superinfection therapy. A preliminary proof-of-principle clinical trial conducted in Hungary demonstrated that superinfection with a non-pathogenic Infectious Bursal Disease Virus (IBDV) shortened the duration of the clinical symptoms in 42 acute hepatitis patients. In addition, fewer patients progressed into chronic disease. More importantly, several advanced decompensated chronic hepatitis patients, who failed conventional therapy, went into long-lasting remission or were stabilized with significant clinical improvement. A striking feature of the IBDV therapeutic vaccine treatment was the regeneration of the cirrhotic liver, which is generally considered to be irreversible. Very importantly, to ensure maintenance of "artificial viremia" by IBDV, it was necessary to administer continuous large doses of the viral preparation over a long period. Nevertheless, no toxicity was associated with the viral therapy.
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